1. Technical Field
The present application relates to a field emitter, and particularly to a carbon nanotube based field emitter.
2. Discussion of Related Art
Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites, energy storage and energy conversion devices, sensors, field emission displays, and nanometer-sized semiconductor devices.
As the carbon nanotubes are used in field emitters, shielding effect between two adjacent carbon nanotubes makes only a few carbon nanotubes emit electrons. Therefore, an emission current density of the field emitter is very small. Improving an emission voltage of the field emitter is often used to improve the emission current density. But improving the emission voltage will damage an emission tip of the field emitter. The damage to emission tips further damages the entire field emitter. Therefore, how to solve the shielding effect between two adjacent carbon nanotubes is a problem in application of a carbon nanotube field emitter.
Moreover, the carbon nanotube field emitter includes an end that is opposite to the emission tip. A high strength of the end is required, in order to support the carbon nanotube field emitter. But the strength of the end of the carbon nanotube field emitter is not very high, affecting stability of emitting electrons, and limiting the widespread use of the carbon nanotube field emitter.
What is needed, therefore, is to provide a carbon nanotube field emitter.